1. Field of the Invention
The present invention as described and claimed in this application relates to a connector used to connect an electrical conduit to a junction box or an outlet box, although it may be used on, for example, a pipe connector system and a post connector system. However, it is not limited to such environments and may be used, not only for example, as a connector for quickly, safely, and reliably connecting a fluid conduit, e.g., piping, system, but may be used in any system wherein a tubular member (rod, pipe, tube, cable, etc.) is required to be connected to an opening or hole.
2. Description of Related Art
Referring to electrical conduit connectors, such connectors are used to connect an electrical conduit or cable to a junction box. The junction box can be a variety of electrical enclosures such as an outlet box, transformer enclosure, circuit panel, lighting fixture, etc. The electrical conduit may be rigid or flexible, or could be in the form of tubing capable of routing electrical wires or cables. Such cables may be non-metallic sheathed cable, portable cord, or a variety of other types of electrical conductors. Commercial and residential buildings alike may have electrical installations that require different types of conduit-to-junction-box connections that utilize electrical connectors. Further, machinery and equipment also require conduit connectors to safely carry electrical wiring through cabinetry or housings.
Two common types of electrical connectors known in the electrical connector field are a snap-in connector and a multi-part locknut connector, which may be comprised of two or more components that include a threaded male end in conjunction with a threaded female locknut. In the case of the two-part locknut connector, the male threaded end is inserted into the junction box through a knockout hole opening. A rigid connection is established by threading the locknut onto the male end in the junction box interior. An example of a two-part locknut connector is found in U.S. Pat. No. 4,885,429 to Schnittker. The snap-in connector is another connector commonly used in the electrical connector field, which utilizes a snap-in portion used to connect quickly the connector to the junction box. Examples of snap-in type electrical connectors may be found in U.S. Pat. No. 2,241,293 to Campbell; U.S. Pat. No. 4,641,863 to Shemtov, and U.S. Pat. No. 5,789,706 to Perkins. A snap-in type electrical connector is also disclosed in U.S. Pat. No. 7,078,623 to Sheehan, incorporated herein by reference, which discloses an electrical connector that utilizes a compression nut and a body. Either of the foregoing types of electrical connectors is integrated with a conduit engagement mechanism at one end, which allows the attachment of conduit, cable, or a variety of types of hollow tubing.
The installation of electrical systems is generally expensive and labor intensive as an electrician must first install the enclosures, route conduit between each enclosure, install connectors, and then pull all necessary electrical wiring through the conduit. Electrical installation is expensive primarily because it is labor intensive. The presently commercially available electrical connectors are labor intensive to install.
Mare particularly, the two-part locknut connectors are shipped from the manufacturer preassembled. Thus, the electrician must first remove the threaded locknut from the male end before it can be installed in the junction box. Once the male end of the connector is placed through the knockout hole in the junction box, the electrician must rethread the locknut onto the connector from the interior of the junction box. Because both hands are required to disassemble the two-part locknut connectors and then reassemble the connectors after insertion in the knockout hole, it is difficult to hold a tool or a piece of conduit while reassembling the connector. Once the locknut is threaded, it must be tightened. In accordance with many building codes and safety regulations, connectors must be reliably and securely attached to junction boxes. To tighten properly the two-part locknut connector, the electrician must use a tool within the interior confines of the junction box enclosure, usually with a set of pliers or a screwdriver. Occasionally, when the proper tool is not available, an electrician will use the wrong tool or simply finger-tighten the connector. Such finger-tightened two-part locknut connectors can eventually loosen causing a strain on the electrical wires and their connections, increasing the probability of an electrical fire or other electrical problems, such as a poor grounding.
Additionally, when the electrician disassembles such a two-part locknut connector, the locknut often is dropped or misplaced. Compounding the situation, the electrician is often in an elevated location, such as, on a ladder, scissor lift, or on scaffolding, because electrical conduit is often installed in out-of-the-way elevated places like in rafters and above ceilings. If the dropped locknut cannot be found, the connector is useless and replaced. Even if the dropped locknut is retrieved, time is wasted and the installation delayed.
Another common problem with present two-part locknut connectors is that the locknut is easily cross-threaded onto the male thread. When this occurs, the electrician must generally use two tools to remove the locknut. On occasion, cross threading the locknut will damage the male threads on the connector making it difficult or impossible to reuse the connector. Again, the electrician must spend time either removing the defective connector or forcing the locknut through the damaged portion of the threads.
A further problem with present two-part locknut connectors is the distance the male end protrudes into the junction box. In some installations, the space inside the enclosure is already minimal. The space limitation becomes an acute problem when an additional connector is installed. Often the male threaded end protrudes well past the depth of the locknut and may interfere with another connector, the apparatus and electrical connections and wiring inside the junction box. Often this requires removal of the excess threading on the male connector. Typically, the electrician saws-off the excess thread, may clip-off some of the receptacle or mounting screws, or completes a combination of space enlarging modifications, all of which prolong installation time and threaten the integrity of the system as designed.
Yet another common problem with present two-part locknut connectors occurs during disassembly of the connector from the enclosure. Electricians may disassemble an installation for a variety of reasons. The disassembly of the two-part locknut connector is more time consuming than the installation. If the locknut was installed properly, that is by tightening it with a tool, and then the locknut must be removed with a tool within the interior confines of the electrical enclosure. If the threads are damaged during disassembly (or even when previously assembled), the connector is useless and must be replaced. If during disassembly the locknut is lost, it must be replaced. If the connector was “modified” during installation, e.g., because of space limitations inside the junction box enclosure, disassembly of two-part locknut connector may be exceedingly difficult or impossible, most likely because the male connector has been damaged.
The snap-in connector presents similar problems. The most significant problem is that these connectors, in most cases, do not create a rigid connection. Because the snap-in portion is sized to accept a variety of junction box wall thickness, it does not rigidly attach to many such boxes. The loose fit may cause electrical continuity problems, which can be a highly dangerous situation because in many applications the box, the conduit, and the connector are intended to be part of the electrical grounding system.
Another problem with the snap-in connector is that, in most cases, the snap-in portion of the connector must deform to flex and fit through a circular hole having a smaller diameter, so its form precludes easy removal or reuse and the connection is typically destroyed upon removal. Generally, any process other than direct force fit installation is time consuming and laborious. Examples of such flexible snap-in connectors may be found in U.S. Pat. No. 3,369,071 to Tuisku, U.S. Pat. No. 3,858,151 to Pasker, and U.S. Pat. No. 6,043,432 to Gretz.
The following are additional U.S. patents and published applications of interest:
U.S. Pat. No. 4,103,101 to Maier
U.S. Pat. No. 4,190,222 to Appleton et al.
U.S. Pat. No. 5,068,496 to Favalora
U.S. Pat. No. 5,905,230 to Marik
U.S. Pat. No. 6,142,818 to Hollesen et al.
U.S. Pat. No. 6,642,451 to Gretz
U.S. Pat. No. 6,727,429 to Koessler
U.S. Pat. No. 6,872,886 to Kiely
U.S. Pat. No. 7,064,273 to Kiely
2012/0024597 to Jafari
To summarize the foregoing, while two-part locknut connectors and snap-in connectors present major challenges to the electrical installer, the two-part locknut connector is often used to provide a wide variety of main power connections and branch circuit connections and snap-in connectors are often used for branch circuit connections. There remains an unfulfilled need to provide a simple, compact, and rigid electrical connector which is reusable and which can be quickly and simply installed or uninstalled from the exterior wall surface of an enclosure and also capable of providing a wide variety of main power applications and branch circuit connections for commercial, residential and equipment connections and applications.